As NJ Transit riders have been plagued by a spate of last-minute train cancellations the past few weeks, much attention has been focused on a longstanding railroad practice that allows engineers to take unscheduled leave.

The practice, called "marking off" isn't as simple as not showing up for work.

Railroad employees do not work 40-hour weeks, 9 a.m. to 5 p.m. Monday through Friday.

Running a railroad is a round-the-clock, seven-days-a week, rain or shine job.

Theresa Gold from Morris Plains knits during the ride to Penn Station to pass the time on Thursday August 9, 2018.
(Photo: Anne-Marie Caruso/NorthJersey)

People crowd the escalator as they leave their trains at Penn Station on Thursday August 9, 2018.
(Photo: Anne-Marie Caruso/NorthJersey)

A train arrives at Denville Station on Thursday August 9, 2018.
(Photo: Anne-Marie Caruso/NorthJersey)

Tim Leonard from Denville keeps busy on his phone during the ride to Penn Station on Thursday August 9, 2018.
(Photo: Anne-Marie Caruso/NorthJersey)

But like the rest of us, railroaders wouldn't want to just work every day. They need rest days. Marking off allows them to take rest days with a minimum of five hours' notice.

In most rail operations, there are enough "extra board" employees who can take last-minute assignments that open up because others have marked off.

But NJ Transit is short nearly 50 engineers of what it needs to operate normally. There's simply no one to pick up all the shifts that open up.